Some movies have That Moment in them, and you know it walking in, and audiences spend a good part of the movie in a kind of limbo preamble, waiting for That Moment to happen, and when it finally does, the audience can relax and enjoy the actual movie.

We’re talking alien chest bursters; we’re talking a guy stuck in a hole in the ground who must detach his arm. In "Soul Surfer," a reasonably accurate, by-the-numbers, uplifting bio-film about Hawaii teen surfer Bethany Hamilton, we’re talking about a really, really big shark bite.

We know it’s coming. The movie even teases with set-ups from a shark’s point of view. But when it happens, the movie suddenly seems to crystallize, turning from a dreamy beach idyll into a frantic scramble for survival.

The shark took almost all of Hamilton’s left arm and a cartoon sandwich bite out of her surfboard. One bite, and fortunately for Hamilton, a neat one. Her massive wound was able to be tied off before all of her blood leaked out, and surgery proceeded apace. She was back in the water within a month or so, eventually surfing competitively.

The problem with sports movies — and this is a true-sports movie, no error — is that they’re built around competition, and it’s always about overcoming odds. In Hamilton’s case, every step is an odd overcome: standing up, paddling without going in circles, being interviewed by the locust-like press. The writers also stirred in a nasty competitor, who, naturally, is the only brunette among the sun-bleached blonde beach bunnies, added an apparently bogus maybe-boyfriend, and dolloped on children afraid of the ocean in tsunami-racked Thailand. Yes, the last part is real.

The trouble with amazing stories like Hamilton’s is that you couldn’t make stuff like this up. Maybe that’s why there’s a dozen screenwriters credited on "Soul Surfer." That’s never a good sign — too many cooks and all that. The committee-write paved over all the interesting cracks.

What we’ve got here is essentially a good-hearted tale about a horrifying mishap and how it turned an enthusiastic surfer girl into a memorable role model. The storytelling is clumsy at times, although its heart is in the right place, particularly when it’s trying to sell us on the mystical power of wave-riding. Hamilton, her family and friends, all live for those moments when they’re sliding down the shoulder of the sea, suspended between the amniotic ocean and the tidal pull of the planets.

Getting that across is pretty tough, and the surfing in "Soul Surfer," whether it’s real or CGI, is portrayed with dignity.

Still, we’re talking after-school special with That Moment as its dramatic spine and a religious undercurrent to solemnize the proceedings.

It’s a sign of the script’s clumsiness that we wonder about the verisimilitude of the lives we’re seeing on the screen. How, for example, do the Hamiltons make a living? In the film, they lounge like Kauai millionaires.

The performances by professional actors, such as the sun-shriveled Dennis Quaid and Helen Hunt as Bethany’s parents, are uniformly fine; those by nonactors not so. "American Idol" alum Carrie Underwood, as a Sunday school teacher with the most eyeliner since Tammy Faye, shouldn’t think about giving up her day job.

As Bethany, AnnaSophia Robb gives a delicate and nuanced performance of a sunny, uncomplicated person whose reason for existence is suddenly torn away. There is a depth to her that would have been heartbreaking in a tougher movie. Here, she simply "overcomes odds" by sheer, scripted willpower.